Abstract: The drop-by-drop evaporation of a liquid or solution is controlled by monitoring the disappearance of each successive droplet and by actuating the deposition of the next droplet until the desired volume is deposited. In the case of a solution, non-volatile residue (NVR) is collected on a deposition surface plate as a relatively small mound. One of a variety of methods may be employed to measure the evaporative behavior of each droplet and to key the deposition procedure. The process is preferably carried out employing a clean deposition surface plate that is maintained at or below the boiling point of the particular liquid or solvent being deposited. The environment is preferably controlled so that inadvertent contamination is precluded from interfering, and thus the method permits the automatic, micro-processor controlled evaporation of liquids with the resultant deposition of non-volatile residues from solutions within relatively short periods of time.